I agree with others, get with the times. I am pretty sure all the major national fast food burgers are 100% beef, no fillers, no preservatives.
I don't eat a ton of fast food anymore, and when I do its usually McDonalds, but I have always enjoyed the Whopper. I had one a few months ago at an airport and tried the Impossible Whopper last week. It's close, but the beef version is still better in my opinion.